You can either use AppWarp cloud or AppWarp S2 (on-premise) depending on the nature of your game.
Here is a ppt which describes the differences between the two.
https://raw.github.com/shephertz/AppWarpDeveloper/master/S2/AppWarpS2.pptx
Both solutions have AS3 samples that will help you to get started.
The pricing for AppWarp cloud is not based on CCUs but instead based on the number of messages exchanged per month. The idea is that its free while you are developing/testing (stay within the free monthly cap) and then only once you release your app and it starts being used by players (monthly message usage goes beyond the free cap) we charge you. You can see the pricing on the site.
AppWarp S2 (on-premise) on the other hand is licensed and the free version has 500 CCUs free.
If you have further questions regarding the pricing - you should contact sales@shephertz.com